On Tuesday, Assistant U.S. Attorney James Brooks alleged in his opening statement that, after the robbery, Knight took post office employee Kimberly Cash as a hostage and drove her truck to a creek, where he'd stashed his white Ford sport utility vehicle.

"He made her lie down in a ditch and then he left," Brooks said.

One week later, Knight cashed more than $2,500 in stolen money orders at the Bank of America in Chattanooga and a week after that, he cashed one stolen money order at the BB&T in Athens, Tenn., Brooks said.

Investigators later traced those money orders to the Whiteside robbery.

Brooks also mentioned two previous post office robbery convictions against Knight, one in 1997 at the Whiteside location, the other in 2001 in Pelham, Tenn.

Knight pleaded guilty to one count of bank fraud Tuesday as the trial began. He faces two more counts of bank fraud, two counts of robbery and one count of kidnapping in the jury trial.

Knight's attorney, federal public defender Antony Martinez, said his client was on Sand Mountain in North Alabama at the time of the post office robbery with his nieces and other family.

Martinez begins his defense this morning.

On Tuesday, in both his opening statements and cross-examination of U.S. Postal Inspector Dianne Bracken, Martinez questioned whether Bracken had focused on his client not because of witness statements but because of his previous criminal history.

"Two days after the robbery, you are already looking and obtaining records on Michael Knight," Martinez told her.

Bracken agreed, but pointed out that the car described by witnesses matched the car that Knight drove.